1 Answer
1

Its could be for dramatization or may be caused by legal and/or
financial issues. Some of the reason are listed as :-

OSs and software interfaces are considered intellectual property and are therefore copyright protected. Most of them are or represent
also a brand. It would require a paid or unpaid agreement by the
copyright holder or brand owner to depict them.
In 24 (TV series) for instance, CTU has been using Apple Displays most of the time while the software shown was proprietary. Apple
remained uncredited . In later seasons however, 24 made heavy use of
"Cisco Teleconference Systems" and showed their logo frequently. The
credits revealed that there was a financial support by Cisco
accordingly.

Product placement is still not legal in many countries without a "proper warning" (e.g. in Germany).

Most OSs or familiarly known software apps don't do as quickly and easily what a screenplay requires them to do. They also don't look as
spectacular and certainly not lucid enough to display the necessary
clarity and/or impressiveness for a quick cut to their interface in
order to reveal at a glimpse what the machine is currently chewing on.

There is an image problem. It has been a strong habit for the last decade to show the good guys using Apple Macs vs. the bad guys using
Windows PCs. it's
certainly not a problem that the bad guys use Windows, but it is a
problem if the good guys win, because the bad guys used Windows
(hacked their system or something fictional that wouldn't - or
actually would! - work in reality). If you look closely, you will
often find Apple computers with the logo rendered unrecognizable,
while the case design is obviously non-PC.
(source)

And sometimes movies/tv show doesn't show the real logo or Operating system just to hide the real product because they are not getting paid for it, i mean producer/director are not willing for free advertisement.

For more details on fake brand endorsing in movies and TV shows refer
following questions-

After looking into it a bit more I agree with the points (1) and (3), and to a certain degree (2). Points (4) and (5) are basically the same, and I'm not sure that's really a problem. Point (6) is just an example of point (1).
–
Oliver_CFeb 18 '13 at 12:27